Bioptical holographic laser scanning system

Abstract

A bioptical holographic laser scanning system employing a plurality of laser scanning stations about a holographic scanning disc having scanning facets with high and low elevation angle characteristics, as well as positive, negative and zero skew angle characteristics which strategically cooperate with groups of beam folding mirrors having optimized surface geometry characteristics. The system has an ultra-compact construction, ideally suited for space-constrained retail scanning environments, and, generate a 3-D omnidirectional laser scanning pattern between the bottom and side scanning windows during system operation. The laser scanning pattern of the present invention comprises a complex of pairs of quasi-orthogonal laser scanning planes, each composed by a plurality of substantially-vertical laser scanning planes for reading bar code symbols having bar code elements (i.e. ladder-type bar code symbols) that are oriented substantially horizontal with respect to the bottom scanning window, and a plurality of substantially-horizontal laser scanning planes for reading bar code symbols having bar code elements (i.e. picket-fence type bar code symbols) that are oriented substantially vertical with respect to the bottom scanning window.

What is claimed is:  
     
       1. A bioptical holographic laser scanning system comprising: 
       a bottom scanning window;  
       a side scanning window;  
       a holographic scanning disc supporting a plurality of holographic scanning facets; and a plurality of laser scanning stations arranged about said holographic scanning disc;  
       wherein each laser scanning station has at least one laser beam folding mirror; and  
       wherein said laser scanning stations collectively produce a laser scanning pattern having a plurality of pairs of quasi-orthogonal laser scanning planes that are projected within predetermined regions of space contained within a 3-D scanning volume defined between said bottom and side scanning windows.  
     
     
       2. The bioptical holographic laser scanning system of  claim 1 , wherein said plurality of pairs of quasi-orthogonal laser scanning planes are produced using said holographic scanning disc supporting holographic scanning facets having high and low elevation angle characteristics and left, right and zero skew angle characteristics. 
     
     
       3. The bioptical holographic laser scanning system of  claim 2 , wherein said plurality of pairs of quasi-orthogonal laser scanning planes are capable of reading a bar code symbol that is orientated with bar code elements arranged in either a substantially vertical (i.e. picket-fence) or substantially horizontal (i.e. ladder) configuration with respect to said horizontal scanning window. 
     
     
       4. A bioptical holographic laser scanning system comprising: 
       a horizontal scanning window;  
       a vertical scanning window;  
       first, second, third and fourth laser scanning stations arranged about a holographic scanning disc supporting a plurality of holographic scanning facets;  
       wherein each laser scanning station includes one or more groups of laser beam folding mirrors; and  
       wherein said first and third laser scanning stations employ groups of laser beam folding mirrors and scanning facets having only high elevation characteristics and left and right skew angle characteristics so as to produce a plurality of pairs of quasi-orthogonal laser scanning planes capable of reading bar code symbol orientated with bar code elements arranged in either a substantially vertical (i.e. picket-fence) or substantially horizontal (i.e. ladder) configuration with respect to said horizontal scanning window.  
     
     
       5. The bioptical holographic laser scanning of  claim 4 , wherein said second laser scanning station employs a group of laser beam folding mirrors and scanning facets having only low elevation characteristics and zero skew angle characteristics so as to produce a plurality of pairs of quasi-orthogonal laser scanning planes capable of reading bar code symbol orientated with bar code elements arranged in either a substantially vertical (i.e. picket-fence) or substantially horizontal (i.e. ladder) configuration with respect to said horizontal scanning window. 
     
     
       6. The bioptical holographic laser scanning system of  claim 4 , wherein said fourth laser scanning station employs a group of laser beam folding mirrors and scanning facets having only high elevation characteristics and zero skew angle characterictics so as to produce a plurality of laser scanning planes capable of reading bar code symbol orientated with bar code elements arranged in either a substantially vertical (i.e. picket-fence) configuration with respect to said horizontal scanning window. 
     
     
       7. The bioptical holographic laser scanning system of  claim 6 , wherein said plurality of pairs of quasi-orthogonal laser scanning planes are produced using S-polarized laser beams directed incident said holographic scanning disc. 
     
     
       8. The bioptical holographic laser scanning system of  claim 4 , wherein four visible laser diodes (VLDs) symmetrically places about said holographic scanning disc are used create said plurality of pairs of quasi-orthogonal laser scanning planes. 
     
     
       9. The bioptical holographic laser scanning system of  claim 4 , wherein a single VLD is used to produce a scan pattern that is projected through said vertical scanning window so as to minimize crosstalk at said laser scanning stations. 
     
     
       10. The bioptical holographic laser scanning system of  claim 1 , wherein the size of the laser beam folding mirrors employed at each said laser scanning station is minimized. 
     
     
       11. The bioptical holographic laser scanning system of  claim 1 , wherein blocking of light return paths by said laser beam folding mirrors is eliminated. 
     
     
       12. The bioptical holographic laser scanning system of  claim 1 , wherein mechanical interference between said laser beam folding mirrors is eliminated. 
     
     
       13. The bioptical holographic laser scanning system of  claim 1 , wherein the angles of the laser scanning beams at said horizontal scanning window is optimized. 
     
     
       14. The bioptical holographic laser scanning system of  claim 1 , wherein said laser scanning pattern provides 360 degrees of scan coverage at a POS station, while the internal mirror-space volume of the scanning system is minimized.